JP2007220177A - Perpendicular magnetic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic recording medium of a perpendicular magnetic recording mode which may improve reproduction output and an S/N ratio. <P>SOLUTION: The magnetic recording medium has; a first recording layer 16; a second recording layer 20 which forms ferromagnetic coupling between the first recording layer; and an intermediate layer 18 formed between the first recording layer 16 and the second recording layer 20, and comprising a non-magnetic layer 18b, and ferromagnetic layers 18a and 18c formed at least in one side between the first recording layer 16 and the non-magnetic layer 18b or between the non-magnetic layer 18b and the second recording layer 20. Thereby, reproduction output of the perpendicular magnetic recording medium can be improved. The S/N ratio of the perpendicular magnetic recording medium can also be improved by suitably controlling the configuration of a ferromagnetic layer and a non-magnetic layer of the intermediate layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic recording medium, and more particularly to a perpendicular magnetic recording medium used for perpendicular magnetic recording.

  A hard disk device, which is a magnetic recording device, is widely used as an external storage device for computers and various portable information terminals such as mobile personal computers, game machines, digital cameras, and in-vehicle navigation systems.

  In recent years, a perpendicular magnetic recording medium capable of increasing the coercive force more than double that of a conventional in-plane recording medium has attracted attention as a recording medium for such a hard disk device. Perpendicular magnetic recording is a magnetic recording method in which magnetic domains are formed so that adjacent recording bits are antiparallel to each other perpendicular to the surface of a recording medium.

  In a magnetic recording medium for perpendicular magnetic recording, so-called “thermal fluctuation”, in which recorded information disappears due to a decrease in magnetic domain when high-density recording is performed, becomes a problem. It is effective to use a material having a large magnetic anisotropy energy Ku for this thermal fluctuation suppression measure. On the other hand, since the recording magnetic field increases as the magnetic anisotropy energy Ku increases, the effect is limited. Therefore, it is a challenge to satisfy both measures against thermal fluctuations and sufficient saturation recording characteristics.

  As a countermeasure, an attempt has been made to make the recording layer a multilayer structure of two or more layers. This is intended to improve recording characteristics by laminating recording layers having different magnetic anisotropies, but it is complicated and difficult to control the composition and structure of each layer in order to obtain the required magnetic characteristics. Further, generally, the film thickness tends to be very thick, and there is a problem that the recording magnetic field from the head is not sufficient.

Against this background, a perpendicular magnetic recording medium called an ECC (Exchange Coupled Composite) medium having a two-layer recording layer in which a nonmagnetic intermediate layer is provided between recording layers has been proposed. The ECC medium is a laminate of two magnetic films with easy axes of magnetization perpendicular to and in-plane with respect to the substrate, or oblique to each other, with a non-magnetic intermediate layer interposed between them to ensure thermal stability. However, it is possible to reduce the recording magnetic field and suppress side erase.
JP 2001-148110 A

  However, in the above conventional ECC medium, since the easy axis of magnetization of the recording layer is oriented obliquely with respect to the substrate normal, the signal output loss is large and a sufficient S / N ratio cannot be ensured. It was. Therefore, a perpendicular magnetic recording medium that can improve the reproduction output and the S / N ratio has been desired.

  An object of the present invention is to provide a perpendicular magnetic recording type magnetic recording medium capable of improving reproduction output and S / N ratio.

  According to an aspect of the present invention, the first recording layer, the second recording layer that forms a ferromagnetic coupling with the first recording layer, the first recording layer, and the second recording layer Formed between the non-magnetic layer, the first recording layer and the non-magnetic layer, and at least one of the non-magnetic layer and the second recording layer. A perpendicular magnetic recording medium comprising an intermediate layer having a ferromagnetic layer is provided.

  According to another aspect of the present invention, the first recording layer, the second recording layer that forms a ferromagnetic coupling with the first recording layer, the first recording layer, and the first recording layer Formed between the non-magnetic layer, the first recording layer and the non-magnetic layer, and at least one of the non-magnetic layer and the second recording layer. A perpendicular magnetic recording medium having an intermediate layer having a formed ferromagnetic layer; and recording of magnetic information in a predetermined recording area of the perpendicular magnetic recording medium and the perpendicular magnetic recording medium provided in the vicinity of the perpendicular magnetic recording medium There is provided a magnetic recording apparatus comprising a magnetic head for reading magnetic information in a predetermined recording area of a magnetic recording medium.

  According to the present invention, the first recording layer, the second recording layer forming a ferromagnetic coupling between the first recording layer, and the first recording layer and the second recording layer are provided. In the perpendicular magnetic recording medium having the formed intermediate layer, the intermediate layer includes at least a nonmagnetic layer, between the first recording layer and the nonmagnetic layer, and between the nonmagnetic layer and the second recording layer. Since it is constituted by the ferromagnetic layer formed on one side, the saturation magnetization Ms of the perpendicular magnetic recording layer can be increased by the ferromagnetic layer of the intermediate layer without changing the characteristics of the first and second recording layers. Thereby, the reproduction output of the perpendicular magnetic recording medium can be improved. Further, the S / N ratio of the perpendicular magnetic recording medium can be improved by appropriately controlling the configuration of the intermediate ferromagnetic layer and the nonmagnetic layer.

  The ferromagnetic layer of the intermediate layer is composed of a plurality of particles made of a ferromagnetic material and a nonmagnetic material filled in the grain boundary of the particles, and the particles are magnetically separated by the nonmagnetic material. As a result, compared with the case where the intermediate ferromagnetic layer is continuously formed in the plane, the magnetic influence of the ferromagnetic layer on the recorded information in the adjacent recording area can be reduced. Thereby, the S / N ratio of the perpendicular magnetic recording medium can be further improved.

[First Embodiment]
A perpendicular magnetic recording medium according to a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a schematic sectional view showing the structure of the perpendicular magnetic recording medium according to the present embodiment, FIG. 2 is a graph showing the dependence of the squareness ratio on the thickness of the nonmagnetic layer, and FIGS. 4 is a graph showing the dependence of the S / N ratio on the thickness of the ferromagnetic layer, and FIG. 5 is a graph showing the change in coercive force with respect to the angle in the measurement direction of the magnetic properties.

  First, the structure of the perpendicular magnetic recording medium according to the present embodiment will be explained with reference to FIG.

  A backing layer 12 made of a soft magnetic material is formed on the glass substrate 10. An intermediate layer 14 made of a nonmagnetic material is formed on the striking layer 12. A first recording layer 16 made of a ferromagnetic material is formed on the intermediate layer 14. An exchange coupling force control layer 18 is formed on the first recording layer 16. The exchange coupling force control layer 18 includes a ferromagnetic layer 18a formed on the first recording layer 16, a nonmagnetic layer 18b formed on the ferromagnetic layer 18a, and a strong layer formed on the nonmagnetic layer 18b. And a magnetic layer 18c. A second recording layer 20 made of a ferromagnetic material is formed on the exchange coupling force control layer 18. As a result, a perpendicular magnetic recording layer 22 including the first recording layer 16, the exchange coupling force control layer 18, and the second recording layer 20 is configured. A protective layer 24 is formed on the perpendicular magnetic recording layer 22.

  The backing layer 12 circulates the recording magnetic field generated from the recording head to form a closed magnetic path for the magnetic flux, and is made of a soft magnetic material, such as a Co-based amorphous alloy or a Ni-based alloy.

  The intermediate layer 14 is a layer for preventing interaction between the backing layer 12 and the perpendicular magnetic recording layer 22, and is made of a nonmagnetic material such as Ru, Cr, Rh, Ir, and alloys thereof. .

  The perpendicular magnetic recording layer 22 is a layer for recording predetermined magnetic information. A ferromagnetic coupling is formed between the first recording layer 16 and the second recording layer 20, and the exchange coupling force between them is controlled by the exchange coupling force control layer 18. The perpendicular magnetic recording layer 22 may be provided with a recording layer having three or more ferromagnetic couplings.

  The first recording layer 16 and the second recording layer 20 have easy axes of magnetization that are perpendicular to the substrate, in-plane, or oblique to each other. The first recording layer 16 and the second recording layer 20 are made of a ferromagnetic material for perpendicular magnetic recording, such as a CoCr alloy or Co granular. The first magnetic layer 16 and the second recording layer 20 may be made of the same material or different materials. When different materials are used, it is desirable that the first recording layer 16 near the glass substrate 10 has a larger perpendicular magnetic anisotropy (Ku) than the second recording layer 20 near the protective layer 24.

  The ferromagnetic layers 18a and 18c are layers for increasing the saturation magnetization Ms of the perpendicular magnetic recording layer 22, and are ferromagnetic materials mainly containing Co, which is a high Ms ferromagnetic material, such as Co, CoCr, CoPt, and CoNi. , CoFe, CoNiFe and the like.

  The nonmagnetic layer 18b is a layer that plays the main role of the exchange coupling force control layer 18 that controls the exchange coupling force between the first recording layer 16 and the second recording layer 20, and is a nonmagnetic material such as Ru. , Cr, Rh, Ir, and alloys thereof. In the present specification, the exchange coupling force control layer may be expressed as an intermediate layer.

  The protective layer 24 is a layer for protecting the surface when the magnetic head scans the perpendicular magnetic recording medium, and is composed of, for example, a carbon film.

  Here, the perpendicular magnetic recording medium according to the present embodiment is mainly characterized in that the exchange coupling force control layer 18 has ferromagnetic layers 18a and 18c made of a ferromagnetic material containing Co as a main component. By providing a layer containing a ferromagnetic material mainly composed of Co, which is a high Ms ferromagnetic material, the saturation magnetization Ms of the perpendicular magnetic recording layer 22 increases, so that the reproduction output can be increased. Further, the S / N ratio can be improved by controlling in detail the structure and film thickness of each layer of the exchange coupling force control layer 18. Further, by using a layer mainly composed of Co whose magnetization easy axis direction is not perpendicular, the magnetization easy axis directions of the first recording layer 16 and the second recording layer 20 can be changed to arbitrary directions. . Thereby, the change rate of the holding force Hc with respect to an angle change can be made smaller. It is not always necessary to provide both the ferromagnetic layer 18a and the ferromagnetic layer 18c, and only one of the ferromagnetic layer 18a and the ferromagnetic layer 18c may be provided.

  Next, a specific configuration of each layer of the exchange coupling force control layer 18 will be described with reference to FIGS.

  FIG. 2 is a graph showing the dependence of the magnetostatic characteristic squareness ratio (SQ) on the film thickness of the nonmagnetic layer 18b. In the measurement of FIG. 2, a Ru film was used as the nonmagnetic layer 18b.

  As shown in FIG. 2, the SQ ratio is changed by changing the film thickness of the nonmagnetic layer 18b. When the film thickness t of the nonmagnetic layer 18b is 0.5 nm or less and 0.8 nm or more, the SQ ratio is approximately 1. This is because when the thickness t of the nonmagnetic layer 18b is 0.5 nm <t <0.8 nm, the first recording layer 16 and the second recording layer 20 have antiferromagnetic coupling via the nonmagnetic layer 18b. It shows that you are doing. Further, when the film thickness t of the nonmagnetic layer 18b is t ≧ 0.8 nm, the recording layers function independently of each other, and thus the effect of the exchange coupling force control layer 18 is not recognized. Therefore, the film thickness t of the nonmagnetic layer 18b needs to be set to t ≦ 0.5 nm.

  FIG. 3 is a graph showing the dependence of the output (Vf8) on the thickness of the ferromagnetic layers 18a and 18c. In the drawing, the plots marked with ● are when the thickness of the first recording layer 16 is 10 nm, and the plots marked with ○ are when the thickness of the first recording layer 16 is 15 nm. In the measurement of FIG. 3, Co films were used as the ferromagnetic layers 18a and 18c. The horizontal axis of the graph indicates the film thickness of each of the ferromagnetic layers 18a and 18c.

  As shown in FIG. 3, it can be seen that the output increases as the thickness of the ferromagnetic layers 18a and 18c increases regardless of whether the thickness of the first recording layer 16 is 10 nm or 15 nm. Accordingly, from the viewpoint of output, it is desirable that the ferromagnetic layers 18a and 18c have a larger film thickness.

  FIG. 4 is a graph showing the dependence of the S / N ratio on the film thickness of the ferromagnetic layers 18a and 18c. The vertical axis indicates a value obtained by subtracting the value of the S / N ratio when the ferromagnetic layers 18a and 18c are not provided, and the larger the value, the greater the effect of the ferromagnetic layers 18a and 18c. In the drawing, the plots marked with ● are when the thickness of the first recording layer 16 is 10 nm, and the plots marked with ○ are when the thickness of the first recording layer 16 is 15 nm. In the measurement of FIG. 4, a Co film was used as the ferromagnetic layers 18a and 18c, and the film thickness of the nonmagnetic layer 18b was 0.4 nm. The horizontal axis of the graph indicates the film thickness of each of the ferromagnetic layers 18a and 18c.

  As shown in FIG. 4, the S / N ratio increases with the thickness of the ferromagnetic layers 18a and 18c and shows a peak value when the thickness of the first recording layer 16 is 10 nm or 15 nm. When this peak value is exceeded, it starts to decrease. If the film thickness of the ferromagnetic layers 18a and 18c is too thick, the S / N ratio becomes smaller than the value of the S / N ratio when the ferromagnetic layers 18a and 18c are not provided. The degree of change depends on the film thickness of the first recording layer 16.

  From the result of FIG. 4, when the film thickness of the first recording layer 16 is 10 nm, the film thickness t of the ferromagnetic layers 18a and 18c is preferably set in the range of 0 <t ≦ 1 nm. When the film thickness of the layer 16 is 15 nm, the film thickness t of the ferromagnetic layers 18a and 18c is preferably set in the range of 0 <t ≦ 2 nm. The film thicknesses of the ferromagnetic layers 18a and 18c are appropriately set so that the S / N ratio in the film thickness of the adopted first recording layer 16 is larger than the value when the ferromagnetic layers 18a and 18c are not provided. It is desirable.

  FIG. 5 shows a change in the holding force Hc with respect to the angle in the measurement direction of the magnetic characteristics. The vertical axis indicates the value of the holding force when the holding force when measured from the direction perpendicular to the film is 100%, and the horizontal axis indicates the angle formed by the direction perpendicular to the film and the measuring direction. The smaller the change in holding force with respect to the change in angle, the higher the side erase resistance. In the figure, the plots with ♦ are when the ferromagnetic layers 18a and 18c are not provided, the plots with ▲ are when the film thickness of the ferromagnetic layers 18a and 18c is 0.5 nm, and the plots with ■ are This is the case where the film thickness of the ferromagnetic layers 18a and 18c is 1.0 nm, and the plot with ● is the case where the film thickness of the ferromagnetic layers 18a and 18c is 1.5 nm. In the measurement of FIG. 5, Co films were used as the ferromagnetic layers 18a and 18c.

  As shown in FIG. 5, it can be seen that the greater the film thickness of the ferromagnetic layers 18a and 18c, the smaller the change in holding force with respect to the change in angle, and the higher the side erase resistance. Therefore, it is desirable that the ferromagnetic layers 18a and 18c have a larger film thickness from the viewpoint of side erase resistance.

  FIG. 6 is a graph showing the dependence of the film thickness of the ferromagnetic layers 18a and 18c on the output when either the ferromagnetic layer 18a or the ferromagnetic layer 18c is provided. The vertical axis represents the value obtained by subtracting the output value when the ferromagnetic layers 18a and 18c are not provided. In the figure, the plots marked with ● are when only the ferromagnetic layer 18a is provided, and the plots marked with ■ are when only the ferromagnetic layer 18c is provided. In the measurement of FIG. 6, Co films were used as the ferromagnetic layers 18a and 18c.

  As shown in FIG. 6, an increase in output can be recognized only by providing either the ferromagnetic layer 18a or the ferromagnetic layer 18c. The effect of increasing the output was higher when only the ferromagnetic layer 18a was provided than when only the ferromagnetic layer 18c was provided. When only the ferromagnetic layer 18c was provided, a decrease in output was observed conversely at a film thickness of 0.5 nm or more with a peak thickness of 0.5 nm.

  From the result of FIG. 6, the effect of increasing the output can be obtained by providing at least one of the ferromagnetic layers 18a and 18c. The relationship between the output and the film thickness differs between the ferromagnetic layer 18a and the ferromagnetic layer 18c, and the film thickness of the ferromagnetic layer 18a and the film thickness of the ferromagnetic layer 18c are not necessarily the same. It is desirable to set as appropriate after ascertaining other characteristics.

  Next, the manufacturing method of the perpendicular magnetic recording medium according to the present embodiment will be explained with reference to FIG.

  First, a backing layer 12 is formed on a glass substrate 10 by depositing a soft magnetic material having a film thickness of, for example, about 50 to 100 nm, for example, a Co-based amorphous alloy or a Ni-based alloy by sputtering, for example.

  Next, a nonmagnetic material having a film thickness of, for example, about 20 nm, for example, Ru, Cr, Rh, Ir, or the like is deposited on the backing layer 12 by, for example, sputtering to form the intermediate layer 14.

Next, a first recording layer 16 made of, for example, CoCrPt—SiO ₂ granular material having a film thickness of about 15 nm is formed on the intermediate layer 14.

  Next, a ferromagnetic material containing, for example, Co having a thickness of about 1 nm, for example, Co, CoCr, CoPt, CoNi, CoFe, CoNiFe, or the like is deposited on the first recording layer 16 by, for example, sputtering, and the ferromagnetic layer 18a. Form.

  Next, a nonmagnetic material having a film thickness of, for example, about 0.5 nm, for example, Ru, Cr, Rh, Ir, or the like is deposited on the ferromagnetic layer 18a by, for example, sputtering to form the nonmagnetic layer 18b.

  Next, a ferromagnetic material containing, for example, Co having a thickness of about 1 nm, for example, Co, CoCr, CoPt, CoNi, CoFe, CoNiFe or the like is deposited on the nonmagnetic layer 18b by, for example, sputtering to form the ferromagnetic layer 18a. To do.

  Thus, the exchange coupling force control layer 18 composed of the ferromagnetic layer 18a, the nonmagnetic layer 18b, and the ferromagnetic layer 18c is formed.

Next, a second recording layer 20 made of, for example, CoCrPt—SiO ₂ granular material having a film thickness of about 5 nm is formed on the exchange coupling force control layer 18.

  Thus, the perpendicular magnetic recording layer 22 composed of the first recording layer 16, the exchange coupling force control layer 18, and the second recording layer 18 is formed.

  Next, a protective layer 24 made of, for example, a carbon film having a thickness of about 4 nm is formed on the perpendicular magnetic recording layer 22.

  Thereafter, a lubricant (not shown) is applied on the protective layer 24 to complete the perpendicular magnetic recording medium according to the present embodiment.

  Thus, according to the present embodiment, the first recording layer, the second recording layer that forms a ferromagnetic coupling with the first recording layer, the first recording layer, and the second recording layer In a perpendicular magnetic recording medium having an intermediate layer (exchange coupling force control layer) formed between the non-magnetic layer, the non-magnetic layer, the first recording layer and the non-magnetic layer, and the non-magnetic layer And a perpendicular magnetic layer formed by the ferromagnetic layer of the intermediate layer without changing the characteristics of the first and second recording layers. The saturation magnetization Ms of the recording layer can be increased. Thereby, the reproduction output of the perpendicular magnetic recording medium can be improved. Further, the S / N ratio of the perpendicular magnetic recording medium can be improved by appropriately controlling the configuration of the intermediate ferromagnetic layer and the nonmagnetic layer.

[Second Embodiment]
A perpendicular magnetic recording medium according to the second embodiment of the present invention will be described with reference to FIGS. The same components as those of the perpendicular magnetic recording medium according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted or simplified.

  FIG. 7 is a schematic sectional view showing the structure of the perpendicular magnetic recording medium according to the present embodiment, and FIG. 8 is a graph showing the dependence of the S / N ratio on the thickness of the ferromagnetic layer.

  First, the structure of the perpendicular magnetic recording medium according to the present embodiment will be explained with reference to FIG. 7A is a cross-sectional view showing the overall configuration of the perpendicular magnetic recording medium according to the present embodiment, and FIG. 7B shows details of the perpendicular magnetic recording layer of the perpendicular magnetic recording medium according to the present embodiment. It is an expanded sectional view.

  As shown in FIG. 7A, the basic film configuration of the perpendicular magnetic recording medium according to the present embodiment is the same as that of the perpendicular magnetic recording medium according to the first embodiment shown in FIG. The main feature of the perpendicular magnetic recording medium according to the present embodiment is that the exchange coupling force control layer 18 is formed of a granular film.

That is, the exchange coupling force control layer 18 in the perpendicular magnetic recording medium according to the present embodiment, Co as shown in FIG. 7 (b), the SiO ₂ is constituted by a SiO ₂ filled Co granulate and its grain boundary Non-magnetic layer 18b 'composed of a ferromagnetic layer 18a' in which particles are magnetically separated from each other, and Ru particles and SiO ₂ filled in the grain boundaries, and Ru particles are separated from each other by SiO ₂ . And a ferromagnetic layer 18 c ′ composed of Co particles and SiO ₂ filled in the grain boundaries, and Co particles are magnetically separated from each other by SiO ₂ .

  By configuring the exchange coupling force control layer 18 in this way, the magnetic effect of the ferromagnetic layer 18a 'and the ferromagnetic layer 18c' on the recording information in the adjacent recording area can be reduced, so that the ferromagnetic layer 18a ' In addition, the S / N ratio can be improved as compared with the first embodiment in which the ferromagnetic layer 18c ′ is not granulated.

  FIG. 8 is a graph showing the dependency of the S / N ratio on the film thickness of the ferromagnetic layers 18a ′ and 18c ′. The vertical axis indicates the value obtained by subtracting the value of the S / N ratio when the ferromagnetic layers 18a 'and 18c' are not provided. The larger the value, the greater the effect of the ferromagnetic layers 18a 'and 18c'. To express. In the measurement of FIG. 8, the film thickness of the first recording layer 16 was 15 nm, and the film thickness of the nonmagnetic layer 18b ′ was 0.4 nm. The horizontal axis of the graph indicates the film thickness of each of the ferromagnetic layers 18a ′ and 18c ′.

  As shown in FIG. 8, the S / N ratio increases with the film thickness of the ferromagnetic layers 18a ′ and 18c ′, reaches a peak value at about 1 nm, and decreases when the peak value is exceeded. When the peak value in FIG. 8 is compared with the peak value in the perpendicular magnetic recording medium according to the first embodiment shown in FIG. 4, the S / N ratio difference can be improved by about twice.

  In addition to Co, CoCr, CoPt, CoNi, CoFe, CoNiFe, or the like can be used as the ferromagnetic material constituting the ferromagnetic layers 18a ′ and 18c ′.

  In addition to Ru, Cr, Rh, Ir, and alloys thereof can be applied to the granular material of the nonmagnetic material constituting the nonmagnetic layer 18b ′.

Further, as a material for separating the granular material of the ferromagnetic material forming the ferromagnetic layers 18a 'and 18c' and the granular material of the nonmagnetic material forming the nonmagnetic layer 18b ', an insulating material containing Si, Al, and Mg is used. For example, a nonmagnetic metal material such as SiO ₂ , Al ₂ O ₃ , MgO, or Ag, Cr can be applied.

Specifically, the ferromagnetic layers 18a ′ and 18c ′ include, for example, Co (SiO) ₅ , Co (SiO) ₁₀ , Co (SiO) ₁₅ , Co (AlO ₂ ) ₅ , Co (AlO ₂ ) ₁₀ , Co (AlO ₂ ) ₁₅ or the like can be used, and Ru (SiO) ₅ , Ru (SiO) ₁₀ , RuCr ₁₀ , RuCr ₁₅ , Ru (MgO) ₇ , Ru (MgO) ₁₅ , Ru (MgO) ₂₀ , Ru (AlO ₂ ) ₅ , Ru (AlO ₂ ) ₁₀ , Ru (AlO ₂ ) ₁₅ , Cr (MgO) ₁₅ , Cr (MgO) ₂₀ , Cr (MgO) _22, etc. can be used. . In addition, the subscript number of each material represents at%.

  Next, the method for manufacturing the perpendicular magnetic recording medium according to the present embodiment will be explained with reference to FIGS.

  First, a backing layer 12 is formed on a glass substrate 10 by depositing a soft magnetic material having a film thickness of, for example, about 50 to 100 nm, for example, a Co-based amorphous alloy or a Ni-based alloy by sputtering, for example.

  Next, a nonmagnetic material having a film thickness of, for example, about 20 nm, for example, Ru, Cr, Rh, Ir, or the like is deposited on the backing layer 12 by, for example, sputtering to form the intermediate layer 14.

Next, a first recording layer 16 made of, for example, CoCrPt—SiO ₂ granular material having a film thickness of about 15 nm is formed on the intermediate layer 14.

Next, on the first recording layer 16, for example, Co and SiO ₂ are sputtered by, for example, a sputtering method, and the film thickness is, for example, 1 nm, and is composed of Co particles and SiO ₂ filled in the grain boundaries. Then, a ferromagnetic layer 18 a ′ in which Co particles are magnetically separated from each other by SiO ₂ is formed. At this time, the film forming gas pressure is set to 0.2 Pa, for example.

Next, Ru and SiO ₂ , for example, are sputtered on the ferromagnetic layer 18a ′, for example, by sputtering, and the film thickness is, for example, 0.4 nm. With the Ru granular material and SiO ₂ filled in the grain boundary, A nonmagnetic layer 18b 'is formed which is composed of SiO ₂ and the Ru particles are separated from each other. At that time, the film forming gas pressure is set to 0.4 Pa or 0.8 Pa, for example.

Next, Co and SiO ₂ are sputtered on the nonmagnetic layer 18b ′, for example, by sputtering, for example, and the film thickness is 1 nm, for example, and is composed of Co particles and SiO ₂ filled in the grain boundaries. A ferromagnetic layer 18 c ′ in which Co particles are magnetically separated from each other by SiO ₂ is formed. At this time, the film forming gas pressure is set to 0.2 Pa, for example.

  Thus, the exchange coupling force control layer 18 composed of the ferromagnetic layer 18a ′, the nonmagnetic layer 18b ′, and the ferromagnetic layer 18c ′ is formed.

Next, a second recording layer 20 made of, for example, CoCrPt—SiO ₂ granular material having a film thickness of about 5 nm is formed on the exchange coupling force control layer 18.

  Thus, the perpendicular magnetic recording layer 22 composed of the first recording layer 16, the exchange coupling force control layer 18, and the second recording layer 18 is formed.

  Next, a protective layer 24 made of, for example, a carbon film having a thickness of about 4 nm is formed on the perpendicular magnetic recording layer 22.

  Thereafter, a lubricant (not shown) is applied on the protective layer 24 to complete the perpendicular magnetic recording medium according to the present embodiment.

  Thus, according to the present embodiment, the first recording layer, the second recording layer that forms a ferromagnetic coupling with the first recording layer, the first recording layer, and the second recording layer In a perpendicular magnetic recording medium having an intermediate layer (exchange coupling force control layer) formed between the non-magnetic layer, the non-magnetic layer, the first recording layer and the non-magnetic layer, and the non-magnetic layer And a perpendicular magnetic layer formed by the ferromagnetic layer of the intermediate layer without changing the characteristics of the first and second recording layers. The saturation magnetization Ms of the recording layer can be increased. Thereby, the reproduction output of the perpendicular magnetic recording medium can be improved. Further, the S / N ratio of the perpendicular magnetic recording medium can be improved by appropriately controlling the configuration of the intermediate ferromagnetic layer and the nonmagnetic layer.

  The ferromagnetic layer of the intermediate layer is composed of a plurality of particles made of a ferromagnetic material and a nonmagnetic material filled in the grain boundary of the particles, and the particles are magnetically separated by the nonmagnetic material. As a result, compared with the case where the intermediate ferromagnetic layer is continuously formed in the plane, the magnetic influence of the ferromagnetic layer on the recorded information in the adjacent recording area can be reduced. Thereby, the S / N ratio of the perpendicular magnetic recording medium can be further improved.

[Third Embodiment]
A magnetic recording apparatus according to a third embodiment of the present invention will be described with reference to FIG.

  FIG. 9 is a schematic view showing the structure of the magnetic recording apparatus according to the present embodiment.

  In the present embodiment, a magnetic recording apparatus using the perpendicular magnetic recording medium according to the first or second embodiment will be described.

  The magnetic recording apparatus 30 according to the present embodiment includes a box-shaped housing body 32 that partitions an internal space of a flat rectangular parallelepiped, for example. In the accommodation space, one or more magnetic disks 34 as recording media are accommodated. The magnetic disk 34 is the perpendicular magnetic recording medium according to the first embodiment shown in FIG. 1 or the perpendicular magnetic recording medium according to the second embodiment shown in FIG. The magnetic disk 34 is mounted on the rotation shaft of the spindle motor 36. The spindle motor 36 can rotate the magnetic disk 34 at a high speed such as 7200 rpm or 10,000 rpm. A lid, that is, a cover (not shown) that seals the housing space with the housing body 32 is coupled to the housing body 32.

  A head actuator 38 is further accommodated in the accommodation space. The head actuator 38 is rotatably connected to a support shaft 40 extending in the vertical direction. The head actuator 38 includes a plurality of actuator arms 42 that extend in the horizontal direction from the support shaft 40, and a head suspension assembly 44 that is attached to the tip of each actuator arm 42 and extends forward from the actuator arm 42. The actuator arm 42 is provided for each of the front and back surfaces of the magnetic disk 34.

  The head suspension assembly 44 includes a load beam 46. The load beam 46 is connected to the front end of the actuator arm 42 in a so-called elastic bending region. Due to the action of the elastic bending region, a predetermined pressing force acts on the front end of the load beam 46 toward the surface of the magnetic disk 34. A magnetic head 48 is supported at the front end of the load beam 46. The magnetic head 48 is received by a gimbal (not shown) fixed to the load beam 46 so as to change its posture.

  When an airflow is generated on the surface of the magnetic disk 34 based on the rotation of the magnetic disk 34, positive pressure, that is, buoyancy and negative pressure act on the magnetic head 48 by the action of the airflow. The balance between the buoyancy and the negative pressure and the pressing force of the load beam 46 allows the magnetic head 48 to continue flying with relatively high rigidity during the rotation of the magnetic disk 34.

  For example, a power source 50 such as a voice coil motor (VCM) is connected to the actuator arm 42. The actuator arm 42 can rotate around the support shaft 40 by the action of the power source 50. Based on the rotation of the actuator arm 42, the movement of the head suspension assembly 44 is realized. When the actuator arm 42 swings around the support shaft 40 while the magnetic head 48 is flying, the magnetic head 48 can cross the surface of the magnetic disk 34 in the radial direction. Based on such movement, the magnetic head 48 can be positioned on a desired recording track on the magnetic disk 34.

  In this way, by configuring the magnetic recording apparatus using the perpendicular magnetic recording medium according to the first or second embodiment, the reproduction output and S / N ratio of the perpendicular magnetic recording medium can be improved. Thereby, the characteristics and reliability of the magnetic recording apparatus can be improved.

[Modified Embodiment]
The present invention is not limited to the above embodiment, and various modifications can be made.

  For example, in the first and second embodiments, the exchange coupling force control layer 18 has a three-layer structure of ferromagnetic layer / nonmagnetic layer / ferromagnetic layer, but the ferromagnetic layer / nonmagnetic layer or nonmagnetic layer / A two-layer structure of a ferromagnetic layer may be used. Further, another layer different from the above-described ferromagnetic layer and nonmagnetic layer may be further inserted.

  In the first and second embodiments, the first recording layer 16 and the second recording layer 20 are made of a granular material. However, the first recording layer 16 and the second recording layer 20 are made of CoCrPt or other recording layer material that is not a granular material. May be.

  Further, the configurations of the backing layer 12, the intermediate layer 14, and the protective layer 24 are not limited to those described in the above embodiment, and can be appropriately changed according to the characteristics required for the perpendicular magnetic recording medium. .

1 is a schematic cross-sectional view showing a structure of a perpendicular magnetic recording medium according to a first embodiment of the present invention. It is a graph which shows the nonmagnetic layer film thickness dependence of the squareness ratio of a perpendicular magnetic recording medium. It is a graph which shows the ferromagnetic layer film thickness dependence of an output. It is a graph which shows the ferromagnetic layer film thickness dependence of S / N ratio. It is a graph which shows the change of the holding force with respect to the angle of the measurement direction of a magnetic characteristic. It is a graph which shows the ferromagnetic layer film thickness dependence of an output. It is a schematic sectional drawing which shows the structure of the perpendicular magnetic recording medium by 2nd Embodiment of this invention. It is a graph which shows the ferromagnetic layer film thickness dependence of S / N ratio. It is the schematic which shows the structure of the magnetic-recording apparatus by 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Glass substrate 12 ... Backing layer 14 ... Intermediate | middle layer 16 ... 1st recording layer 18 ... Exchange coupling force control layer 18a, 18c, 18a ', 18c' ... Ferromagnetic layer 18b, 18b '... Nonmagnetic layer 20 ... 1st Two recording layers 22 ... perpendicular magnetic recording layer 24 ... protective layer 30 ... magnetic recording device 32 ... housing body 34 ... magnetic disk 36 ... spindle motor 38 ... head actuator 40 ... spindle 42 ... actuator arm 44 ... head suspension assembly 46 ... Load beam 48 ... Magnetic head 50 ... Power source

Claims (10)

A first recording layer;
A second recording layer forming a ferromagnetic coupling with the first recording layer;
Formed between the first recording layer and the second recording layer, and between the nonmagnetic layer, the first recording layer and the nonmagnetic layer, and the nonmagnetic layer and the second recording layer. And an intermediate layer having a ferromagnetic layer formed on at least one of the layers. The perpendicular magnetic recording medium according to claim 1, wherein
The ferromagnetic layer includes a plurality of particles made of a ferromagnetic material and a nonmagnetic material filled in a grain boundary of the particles, and the particles are magnetically separated by the nonmagnetic material. A perpendicular magnetic recording medium. The perpendicular magnetic recording medium according to claim 2, wherein
The nonmagnetic layer includes a plurality of granular materials made of a nonmagnetic material and another nonmagnetic material filled in a grain boundary of the granular material, and the granular materials are separated by the other nonmagnetic material. A perpendicular magnetic recording medium characterized by the above. The perpendicular magnetic recording medium according to claim 2 or 3,
The other nonmagnetic material is an insulating material containing Si, Al, and MG, Ag, or Cr. The perpendicular magnetic recording medium according to any one of claims 1 to 4,
The perpendicular magnetic recording medium characterized in that the ferromagnetic material constituting the ferromagnetic layer is Co or an alloy containing Co as a main component. The perpendicular magnetic recording medium according to any one of claims 1 to 5,
The perpendicular magnetic recording medium, wherein the nonmagnetic material constituting the nonmagnetic layer is Ru, Cr, Rh, Ir, or an alloy thereof. The perpendicular magnetic recording medium according to any one of claims 1 to 6,
The perpendicular magnetic recording medium, wherein the nonmagnetic layer has a thickness of 0.5 nm or less. The perpendicular magnetic recording medium according to any one of claims 1 to 7,
The perpendicular magnetic recording medium, wherein the ferromagnetic layer has a thickness of 2 nm or less. The perpendicular magnetic recording medium according to any one of claims 1 to 7,
The perpendicular magnetic recording medium, wherein the ferromagnetic layer has a thickness of 1 nm or less. Formed between the first recording layer, the second recording layer forming a ferromagnetic coupling between the first recording layer, the first recording layer and the second recording layer; An intermediate layer having a nonmagnetic layer and a ferromagnetic layer formed between at least one of the first recording layer and the nonmagnetic layer and between the nonmagnetic layer and the second recording layer; A perpendicular magnetic recording medium having:
A magnetic head provided in the vicinity of the perpendicular magnetic recording medium and performing recording of magnetic information in a predetermined recording area of the perpendicular magnetic recording medium and reading of magnetic information in the predetermined recording area of the perpendicular magnetic recording medium. A magnetic recording apparatus.

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